tation may not afford us, *à posteriori*, some legitimate inductions.

What does the Newtonian law declare?—That all bodies attract each other with forces proportional to their quantities of matter and inversely proportional to the squares of their distances. Purposely, I have here given, in the first place, the vulgar version of the law; and I confess that in this, as in most other vulgar versions of great truths, we find little of a suggestive character. Let us now adopt a more philosophical phraseology:—*Every atom, of every body, attracts every other atom, both of its own and of every other body, with a force which varies inversely as the squares of the distances between the attracting and attracted atom.*—Here, indeed, a flood of suggestion bursts upon the mind.

But let us see distinctly what it was that Newton *proved*—according to the grossly irrational definitions of *proof* prescribed by the metaphysical schools. He was forced to content himself with showing how thoroughly the motions of an imaginary Universe, composed of attracting and attracted atoms obedient to the law he announced, coincide with those of the actually existing Universe so far as it comes under our observation. This was the amount of his *demonstration*—that is to say, this was the amount of it, according to the conventional cant of the "philosophies." His successes added proof multiplied by proof—such proof as a sound intellect admits—but the *demonstration* of the law itself, persist the metaphysicians, had not been strengthened in any degree. "*Ocular, physical* proof," however, of attraction, here upon Earth, in accordance with the Newtonian theory, was, at length, much to the